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Q: False positive result on a Urine Drug Screen ( Answered 4 out of 5 stars,   7 Comments )
Subject: False positive result on a Urine Drug Screen
Category: Science > Chemistry
Asked by: jodiew64-ga
List Price: $25.00
Posted: 22 Nov 2006 08:02 PST
Expires: 22 Dec 2006 08:02 PST
Question ID: 784817
I have been a Registered Nurse for nearly 20 years and work in an
environment where mandatory drug testing is the rule.  I have had 5 or
6 drug test over the years and have never ever tested positive for any
illegal drug(s). Never even a false positve result before. Simply,
because I don't do drugs!  I recently decided to do some PRN work at a
small local hospital who has a real need for nurses due to the fact
that they have been in financial ruin for about 8 or 9 years
now....threatened with closing their doors about once or twice a year
and therefore can not keep staff....but they were recently bought out
by an out of state, large corporation who is promising good
things...they are still going through the legal approval
process....anyways....I went for my physical and drug screen on the
10th of Nov.  Was then notified on the 20th of Nov. that my test
result had come back positive for amphetamines.  The girl stated that
they would have sent the urine out for the GC/MS but she didn't see
the results from their lab until the 20th.  She asked if I would come
back in for a repeat test....I replied absolutely.  There must be some
mistake here....I have never done illegal drugs in my life! As well, I
am a church going mother or two children...ages 16 and 11.  I was
totally mortified by this news!  When I went in for the repeat test
yesterday, 11/21, I questioned the labs process of no
chain-of-custody....the first time I went....I was given the cup to
urinate in and told the bathroom is over there...I stated, now you do
not want me to flush the toliet or wash my hands until I hand this
urine to you, right?  The lab tech said, "oh we don't do that here." 
This did raise an eyebrow with me as I am a very analytical, detail
oriented personality.  Then, on my repeat visit at 0750am on the 21st,
I did question their practice of no chain-of-custody and was again
told by the head of H.R. and the lab tech that "we don't do that
here."  I was then told that they would re-run the test at their lab
and if it came back positive again that they would send it out for
confirmation.  It did, again, come back positive in their lab.  So, I
was told that it was being sent out at 5pm that day.  I can not think
of any over-the-counter medications that I have taken besides two
multi symptom pamprin tablets the week of the 1st test and a couple of
ibuprofen this past week prior to the second test.  I do drink a lot
(4 to 5 bottles a day)of Propel Fitness Water which is vitamin
enhanced....loaded with B vitamins....3,5,6 & 12. As well as vitamins
C & E.  I also drink a lot of coffee with Vanilla Spice Chai creamer. 
Would either of these products cause a false positve for amphetamines?
 I also understand, from my on line research, that certain medical
conditions such as kidney infection, kidney disease, diabetes and
liver disease can casue a false positive result on the cheaper test. 
I do have a history of kidney infections & multiple kidney stones.  I
understand that the GC/MS is considered to be the "Gold Standard" for
urine drug screens.  This test will identify the false positive
culprit, correct?  I am extremely upset about this.  I was made to
feel like a criminal...guilty of a crime that I did not commit.  As
well, the fact that they do not use a Chain-of-custody systme is
alarming.  What if someone there compromised my specimen?  I am an
extremely qualified individual with a Bachelor of Science in Nursing
and a Masters of Science degree in Mgt. of Non profit Organizations. 
I have 20 years of nursing was
suggested that maybe someone is threatened by my wanting to pick up
extra time there...perhaps thinking I may try to take over her job!  I
guess stranger things have happened!  I would sincerely appreciate any
information that you can offer that may relieve my anxiety related to
this situation!   I was told to report on Monday for orientation. 
But, was told that if the confirmation test comes back positive that I
would be told to go home!  This whole situation is so humiliating!!!!
Subject: Re: False positive result on a Urine Drug Screen
Answered By: sublime1-ga on 22 Nov 2006 13:32 PST
Rated:4 out of 5 stars

I worked in the field of mental health for 25+ years, and came
to have a great appreciation for the invaluable role played by
the nurses with whom I worked, so I understand your shock and
dismay with this unpleasant situation casting doubts upon your

First, let me address the substances which might be causing
false positives, though nothing you've named seems suspect.
Vanilla Spice Chai creamer seems very unlikely, and a search
for coffee in relation to a false positive turns up only this
one, unexplained cautionary note from Drug Testing 101:

"Drinking plenty of water and juices helps rid the body of
 impurities. Stay away from coffee, tea and carbonated
 beverages if possible. Also refrain from drinking alcohol.
 While alcohol is being metabolized the body does little
 else in the way of processing other foods and ingestibles,
 preferring to concentrate on the alcohol because it is an
 extremely rich source of energy and sugars. In other words,
 consuming alcohol slows the body's process of clearing
 itself of other impurities."
Much more information on the page:

Ibuprofen has been known to cause false positives for THC, the
active ingredient in marijuana, but not for amphetamines.

From the LegalMatch website:
"Medications that contain ephedrine or phenypropanolamine, such
 as nasal sprays or diet products, could cause a false positive
 for amphetamines."

From the NYU Medical Center:
"...remember that liver problems, kidney problems, or diabetes
 may cause a false-positive for amphetamines..."

From the AskDocWeb site:
"Can Fioricet cause a false positive for amphetamines?"

"Yes it can, it is a barbiturate."

and, finally, the motherlode...

"The chances of you getting a false positive depends on the
 quality of the laboratory that does the testing. There seems
 to be about 1,200 of these labs in the United States currently
 testing for drugs. Less than a 100 of these meet federal
 standards and most of the individual states do not regulate
 drug test labs. The number of false positives returned range
 from 4% to over 50%, depending on the lab.

 A concern here is that, if your company tests for drug useage,
 they are probably not required to use a certified drug testing
 lab, which means you have a greater chance of getting a false

 Listed below are all the substances, that we found, that can
 cause a false positive drug test result. With your help, this
 will grow into a comprehensive list.

Substances that cause false positives [not just for amphetamines]

Amoxicillin - False positives for cocaine
Anti-anxiety pills - Many will test positive for Benzodiazepines
Antibiotics - False positives on Heroin Tests
Asthma medications (Marax, Bronkaid tablets, Primatine Tablets)
B2 vitamin
Blue Lettuce
Bronkaid tablets
California Poppy
Cough medicines - See if any ingredients are on this list
Cough suppressants with Dextromethorphan (DXM)
Diazepam (generic name for valium)
Diazepam False positives for PCP
Dristan Nasal Spray
Dronabinol (Marinol)
Elavil - False positives for opiates for up to three days
Ephedra (Ma Haung)
Ephedrine based compounds
Excedrin IB
Fioricet and derivatives
Hempseed Oil
Ibuprofen - False positives for Marijuana
Kidney disease
Kidney infection
Lettuce - Both Prickly and Blue
Liver disease
Liver infection
Lortab - an opioid analgesic
Ma Huang
Matilija Poppy
Menstrual cramp medications like Midol and Trendar
Mormon Tea
Most prescription pain medications
Nasal decongestants - False positives for Amphetamines
Nyquil Nighttime Cold Medicine - False positives for Methadone up to 2 days
Orudis KT
OTC diet aids with phenylpropanolamine (Dexatrim, Accutrim)
Over-the-counter nasal sprays (Vicks inhaler, Afrin)
Poppy seeds
Prescription sleeping pills
Prickly Lettuce
Prickly Poppy
Primatene-M containing perylamine
Primatine Tablets
Pseudo ephedrine
Quinine water - False positives for opiates
Red Poppy
Robitussin Cold and Flu
Tonic water
Tylenol Sinus
Tylenol with codeine
Vicks Formula 44M containing Dextromethorphan
Vicks inhaler
Vicks Nasal Spray
Vicks Nyquil
Vitamin B2
Wygesic "
[note the mention of vitamin B2]

From the Phentermine Forum:

"Phentermine can cause a false positive for amphetamines on some
 drug test. These are urine test."


"I do not and have not done illegal drugs however I have tested
 positive for amphetamines.The only medication I am on is 300mg
 wellbutrin per day.";read=743


"I tested positive for amphetamines after taking DXM a couple days

"Dextromethorphan hydrobromide (DXM for short) is an antitussive
 drug that is found in many over-the-counter cold remedies and
 cough syrups."

From an article by Anthony D. Crane about drug testing in prison:

"FENOPROFIN (active ingredient--Nalfon) tested positive for Marijuana,
 Amphetamines, Barbiturates, and Methaqual one."


"PHENYLPROPAN-OLAMINE (active ingredients--Actifed, Alka-Seltzer,
 Alka-Selzer Plus, Allerest, Caldecon, Contac, Dietac, Dimetapp,
 4-Way Nasal Spray, Ortain, Sinarest, Triaminicin) tested positive
 for Amphetamines."

I think that pretty well covers substances which might cause a
false positive. What remains is what to do. The following article
on Issues notes that:

"A number of organizations have submitted proof as to the
 inaccuracies of drug testing. indicates
 that the low cost, easy to administer tests often produce both
 false-positive and false negative results, and that all positive
 results should be backed up by the more accurate Gas Chromatograph
 /Mass Spectrometry (GC/MS) test. The sad fact is, everyone seems
 to be under the scrutiny of drug testing even though the medical
 field realizes that these test may be inaccurate. The American
 Civil Liberties Union (ACLU) has fought the issue of drug testing
 for years, on both the merit of drug tests as well as violation
 of individual civil rights, still their challenge has remained
 unheard. An article by offers a statistical insight
 into what percentage of innocent people have incorrectly been
 identified as drug users as a result of inaccurate drug tests,
 which leads us to believe that in America, where drug testing
 is concerned, we are guilty until proven innocent."

The article on notes:

"The population of people identified as drug users consists of
 individuals who actually are drug users (1.98% of the employees
 tested) and incorrectly identified individuals who actually are
 not drug users (0.98% of the employees tested). The percentage
 of people identified as drug users who are actually innocent
 can be calculated as follows:

    Pinnocent = Pcw /( Pcw +Pdr )

                     = (0.98%) /(0.98% + 1.98%)

                     = .331 or 33.1%

 The wild eyed claim that a third of all people accused of drug
 use will be innocent is not so ridiculous after all."

And, from the first link I gave, at LegalMatch:

"An employment lawyer can help an employee who has not been hired,
 who was fired, or who has been denied benefits because of a false
 positive drug test result.  If you believe your drug test produced
 a false positive result, an experienced employment attorney can
 help protect your rights."

As for the reliability of the GC/MS, it identifies the metabolites
of the substance in question. If the metabolites are identical, as
noted in this excellent article on 'drug testing accuracy and 
standards', even the GC/MS has been said to show a false positive
for marijuana due to Ibuprofen use:

"3.2.1 Ibuprofen: Ibuprofen is a common pain reliever that (even
 in low dosages) used to cause a false THC positive on the EMIT
 test. The EMIT has been changed to use a different enzyme to
 eliminate false positives due to Ibuprofen. Ibuprofen in very
 high doses will still interfere with both the EMIT and the GC/MS.
 There is some conflicting data here because some sources say that
 the GC/MS tests can distinguish between Ibuprofen and THC (as well
 as other over-the-counter drugs)."

On the other hand, it can distinguish between poppy seeds and opium:

"Although poppy seeds have the same metabolites as opium, these
 metabolites are shown to have different patterns when viewed
 with the GC/MS."

The page also has extensive information about the relative accuracy
and standards of different labs, asserting that only the ones that
are certified by the NIDA or CAP are accurate:

"NIDA (The National Institute of Drug Abuse) is the government
 organization responsible for regulating the drug-testing industry.
 The vast majority of urine drug screens done these days conform
 to NIDA specs, and ALL testing associated with the government
 (department of transportation, etc.) complies with the NIDA
 standard. It is NIDA that decides what the "safe" cutoffs are
 to avoid false positives..."


"CAP (College of American Pathologists) also certifies
 laboratories the way NIDA does. NIDA keeps it's labs in
 check by sending positive and negative double-blind samples.
 Lab personnel does not know what samples came from NIDA. If
 the lab results are wrong, NIDA may take away the lab's
 certification. Only labs that perform the GC/MS on site
 can be NIDA certified. Labs that send samples to another
 laboratory for GC/MS confirmation are ineligible for NIDA

So, other than insisting that another test be conducted by one of 
the ~100 labs that meets federal standards for drug testing (which
suggestion could be turned down by a prospective employer), it 
comes down to the fact that employers are essentially free to act
on the information provided by the tests, especially if they do
a second one in the form of a GC/MS, and seeking legal assistance
may be your only recourse, should you deem it worthwhile.

Being that nurses are in great demand, it shouldn't be difficult
to obtain employment elsewhere, and the results of a failed test
from an employer who subsequently declines to hire you should not
be made available to any other agencies without a release of 
information on your part.

Beyond that, it would seem prudent to familiarize yourself with the
recommendations on the Drug Testing 101 page, regarding strategies
to decrease the likelihood of a false positive in any future tests
with potential employers.

Please post a Request for Clarification if you have any questions.


Additional information may be found from further exploration
of the links provided above, as well as those resulting from
the Google searches outlined below.

Searches done, via Google:

"cause a false positive for amphetamines"

"tested positive for amphetamines"

coffee "false positive for amphetamines"

GC/MS testing
jodiew64-ga rated this answer:4 out of 5 stars
Very quick and reassuring response.  Thank you.

Subject: Re: False positive result on a Urine Drug Screen
From: redhoss-ga on 22 Nov 2006 09:09 PST
Wow, Dr. Phil should look into this. My daughter is a nurse and I sure
hope things work out for you.
Subject: Re: False positive result on a Urine Drug Screen
From: probonopublico-ga on 22 Nov 2006 20:51 PST

One of my daughters is also a nurse here in the UK.

All the Very Best in sorting this out.

Subject: Re: False positive result on a Urine Drug Screen
From: daniel2d-ga on 23 Nov 2006 19:41 PST
Humiliating?  Get some self-helf books on self-esteem and handling
stressful situations.  They did a test and sometimes the tests come
back with wrong results.
Let them send it out and see what happens.  If that test comes back
negative then you're O.K.  If you really want this job, offer to go to
a certified lab and pay for the test yourself with the results sent to
you and them. You've already observed that their methods are somewhat

As for chain of custody - this isn't a criminal case, just a
pre-employment requirement.  Yes, they should have better controls but
since the most that can happen is that a prospective employee doesn't
get hired they just have to be reasonable in the process.
Subject: Re: False positive result on a Urine Drug Screen
From: probonopublico-ga on 23 Nov 2006 21:58 PST

I couldn't diasagree more!

Employers who are cavalier about such tests are not being responsible
and should be taken to the cleaners.

I am sure that Jodie can handle the situation without resort to any
self-help books but what about the other poor devils who can't?

It now makes me wonder about other situations where tests have
supposedly proved positive.

The whole thing is an ABSOLUTE disgrace.

Subject: Re: False positive result on a Urine Drug Screen
From: jodiew64-ga on 23 Nov 2006 23:35 PST
My sincere thanks to sublime1 for your answer.  As well, thanks to
most of you for your sincere and reassuring comments.  And, to
Daniel....just this...I have a nursing license to protect....thank
you.  This is not an issue of self esteem or handling
primary job is working as a registered nurse in a very busy...49,000
visit per year emergecny dept.  I handle stress quite well, thank you!
 I was just looking for some reassurance from the outside as this is
not a matter that you discuss openly with your fellow employees.
Subject: Re: False positive result on a Urine Drug Screen
From: jodiew64-ga on 24 Nov 2006 13:40 PST
Good news to all who responded.  I received a phone call, this
afternoon, from the H.R. director stating that my urine drug screen
confirmation, using the GC/MS method, had come back NEGATIVE for any
type of drugs.  She was trying to be so very nice.  However, she never
did offer an apology for the agony that they put me through these last
few days!  Oh well, the important thing is that this alarming ordeal
has come to end.  Thanks again, everyone!  : )
Subject: Re: False positive result on a Urine Drug Screen
From: sublime1-ga on 24 Nov 2006 16:01 PST

I'm very pleased to hear of your positive, negative outcome...  ; )

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